Sound-muffling attachment for telephonic apparatus.



L. B. GRAY.

T SOUND MUFFLING ATTACHMENT FOR TELEPHONIC APPARATUS.

APPLICATION FILED FEB. 25 I915.

Patented Apr. 4, 1916.

am \N QN LAWRENCE B. GRAY, OF BOSTON, MASSACHUSETTS.

S'OUND-IIUFFLING ATTACHMENT FOR TELEPHO'NIG APPARATUS.

Specification of Letters Patent.

Application filed February 25, 1915. Serial N 0. 10,489. I

To all whom it may] concern.

Be it known that I, LAWRENCE B. GRAY, .a citizen of the United States, and resident of Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Sound-MuiHing Attachments for Telephonic- Apparatus, of

' which the following is a specification.

This invention relates to sound muffling or deadening attachments eitlierfor telephone transmitters, to enable the user to speak into the transmitter without being easily overheard by gt -iople nearby, 'or for telephone receivers to curlade externalv sounds from the ear of the user of a receiver.

The invention consists in the improve-'2 the face of the transmitter and closely hugs I ments hereinafter described and claimed, having for then ob3ect the production of an effective mufiling attachment adapted to be quickly applied to and removed from a telephonic'apparatus part or member, and also adapted, when embodied'in a transmitter at- I tachment, to be supported by both the body and the mouthpiece of the transmitter.

Of the accompanying drawings',F1gure lrepresents an end view of a transmitter attachment embodying my invention; Fig.

2 represents a section on line 2-2 of Fig. 1, and a side view of a transmitter to which the attachment is operatively applied; Fig. 3

represents a fragmentary section on line 3--3 of Fig. 2 Fig; 4 represents an end-view of a receiver attachment embodying the myention; Fig. 5 represents a section on line 5.5 ofFig.4. p

The same reference characters indicate the same or similar parts in all the views.

In Figs. 1, 2 and 3, 12 represents a tubular casing or shellwhich is contractedat one end and there provided with a mouthpiece 13. The opposite end of the casing is provided with a socket formed to receive the body 14, of a telephone transmitter, said socket including a'rigid annular portion 15 and a rigid end portion 16. The socket also includes a compressible annular inner portion 15' backed by the rigid portion 15 and adapted to closely hug the periphery of the transmitter body. The inner portion 15* and its projections may be formed from a strip of relatively thick'felt or other compressible material which has transverse. thickened portions or rldges extendingacross one of lts sides forming pro ect1ons 15 Said projections are so arranged that they are under considerable rad al compres- I movable.

' sion when applied to the transmitter, so that 'the attachment is engaged with the transan annular facing layer 16 preferablyof felt, backed by-the rigid end portion 16 and formed to bear on the face'of the trans mltter and prevent the passage of sound vibrations. The layer 16 is preferably eX- 1 tended inwardly as shown, so that it covers the base of the usual mouthpiece 18, the inner margin of the layer 16 being provided with radial slits 16 which adapt the layer to pass freely ,over the larger end of the mouthpiece-18. The rigid end portion 16 forms an abutment or stop which prevents" endwlse displacement of the compressible annular portion 15 by the pressure exerted upon it in applying it'to the perimeter of the transmitter so that said compressible portion yields only in a radial direction, and is therefore caused to act as a chuck firmly grasping the transmitter: p 19 represents an annular inner wall Wh1ch is joined to the socket end 16, and artially subdivides the. interior of the easing into an inner air chamber 20 containing the mouth piece 18, and an outer air chamber 2' Which extends to the contracted end of the casing 12.

Joined to the wall 19 is an annuliar head 23, which forms the inner end of the inner air chamber 20. Joined to theinner mar-. gin of the head 23 is a tapering tubular sound conducting nembr" 24;, which "is formed to enter the outer end of the tapering mouthpiece 18. The member or con: ductor 241s in almeme'nt with the casing mouthpiece 13, and its functionsare to con duct sound waves into the mouthpiece 18, and toaid in detachably engaging the attachment with the transmitter, the attachment being supported partly by the body and partly by the mouthpiece of the transmitter, and being readily applicable and re 3 25 represents a tapering tubular extension of the mouthpiece I. pro ect1ng into the contracted end of Patented Apr. 4, 1916.

casing 12, and

serving to conduct sound Waves toward the transmitter mouthpiece. is separated from the head 23 by an air space 27, which communicates with the'outer air chamber 521. Elaid air space is partly obstructed by annular ballie rings 28, 29 of felt or other sound absorbing material, said rings being preferably slotted. The object of said air space and battle rings is to break up and absorb sound Waves and thus increase the mulliing eliiciency of the attachment. To further increase said eiliciency, I preferably provide the head :23 With an annular flange 80, which partially subdivides the outer air chamber 21.

The rigid parts of the attachment be of a suitable metal such as aluminum or papier-m ch or other moldable material.

I have demonstrated by practical tests that the interruption of the inner Wall of the outer air chamberfZl by the space 27 containing the sound absorbing baflie rings, renders the attachment more efficient as a sound muffler than would be the case if the extension 25 and head 23 were brought together to form a continuous or uninterrupted sound conducting passage.

The tapering conductor 24 forming as de scribed a part of the sound conducting passage through the attachment and a means for engaging the mouthpiece 18'to cause the latter to aid in supporting the attachment, also forms a part of the Wall of the inner air chamber 20.

The socket portion of the above-described attachment may be utilized as a part of an attachment for the ear piece of a telephone receiver 35, as shown by the modification illustrated by Figs. l and 5, the attachment being composed of an annular body 36 of Wood, papiermach, hard rubber, metal or other suitable material. Said body has at one end, an annular ear piece 37 formed to surround the external ear of the user of the receiver, and bear closely on the hair or the side of the i ad around the ear, and thus muflle or shut out external sounds. The opposite end of the body has a socket Which. includes a rigid annular portion 38, and an inner annular portion 88* of compressible material such as felt, hacked by the rigid outer portion, said inner portion being pro vided With transverse ridges or projections 38*, the portion 38" and its projections being formed and applied like the above-mentioned portion and projections 15 The projections 38* are adapted to closely hug and be compressed radially by the periphery of the receiver head. The socket also in cludes a rigid end portion preferably of the stepped form shown by Fig; 5, and a stepped facing layer backed by the rigid portion 39 and adapted to hear on the outer end of the receiver head, Said facing layer is preferably composed of two felt igs 39,

The extension 25 a portion of the these rings forming steps which are compressible by the usual stepped end face surrounding the conducting passage communicating with the diaphragm of the receiver. The rigid end portion 39 acts as a stop or abutment preventing endwise displacement of the compressible portion The attachment is adapted to be quickly applied to and removed from the receiver, and constitutes an effective sound-mullling ear piece extension thereof.

The compressible projections on the cylindrical socket portion are adapted to fit transmitters or receivers of different sizes, without marring or scratchingthe same.

I claim:

l. A mufiling attachment comprising a tubular casing having a. mouthpiece at one end, a socket at the opposite end adapted to detachably engage the body of a telephonetransmitter, and an intermediate sound-conducting member rigidly supported in the casing and formed to enter and detachably engage the tapering mouthpiece of the transmitter.

2. A muilline' attachment comprising a tubular casing having a mouthpiece at one end, a socket at the opposite end adapted to detachably engage the body of a telephone transmitter, and a tubular inner Wall eX-' tending into the casing from said socket and provided at its inner end with an annular head and With a tapering tubular soundconductor projecting from said head and formed to enter the tapering mouthpiece of the transmitter, said inner Wall subdividing casinginto an inner air chamber formed to surround the transmitter mouthpiece and closed at one end by said head, and an outer air chamber extending to the mouthpiece end of the casing.

3. A mufiling attachment comprising a tubular casing having a mouthpiece at one end, a socket at the opposite end adapted to detachably transmitter, a tubular inner Wall extending into the casing from said socket and pro vided at its inner end With a lar sound conductor formed to enter the transmitter mouthpiece, and a tubular mouthpiece extension projecting inwardly from the casing mouthpiece, said inner wall and mouthpiece extension being separated from the casing Wall by an air chamber.

4. A muflling attachment comprising a tubular casing having a mouthpiece at one end, a'socket at the opposite end adapted to detachably engage the body of a telephone transmitter, a tubular inner Wall extending into the casing from said socket and provided at its inner end with an annular head having means for engaging the transmitter mouthpiece, a tubular mouthpiece extension projecting inwardly from the casing mouthpiece, said inner Wall and mouthpiece extenengage the body of a telephone tapering tubumaterial adapted to be compressed by the periphery of the transmitter body, and an inner end portion adapted to bear on the outer face of said body and having a facing layer of compressible material formed to bear on the face of the transmitter body, said facing layer' being extended inwardly to form a flexible annular flap adapted to sion being separated from the casing wall by an air chamber, said extension being separated from said annular head by an air space communicatingvvith said airehamber, an non-resonant annular bafile rings of soundabsorbing material, partially abstracting said space and attached to the said mouth and head.

piece extension 5. A mufliing attachment comprising a ass over the transmitter mouthpiece.

1o tubular casing having a mouthpiece at one 7. A sound-muifling attachment comprisend, a socket at the opposite end adapted to ing an annular sound-conducting body havdetachably engage the body of a telephone ing at one end an annular sound-conducting transmitter, and a tubular inner Wall exmember and at the other end a socket formed tending into the casing from said socket for detachable application to a telephone 15 and provided at its inner end with an annupart, and including a rigid annular outer lar head and with a tapering tubular soundportion having a relatively Wide inner surconductor projecting from said head and face,and a compressible annular inner porformed to enter the tapering mouthpiece of tion backed by the rigid outer portion and the transmitter, said inner Wall subdividing having spaced compressible projections 7-0 a portion of the casing into an inner air adapted to be radially compressed by and to chamber formed to surround the transmitter closely hug said telephone part, said socket mouthpiece and closed at one end by said also including a rigid end portion constitut head, and an outer air chamber extending to ing a stop which confines the said compressithe mouthpiece end of the casing, said head ble annular portion against endWise disbeing provided with an outer flange parplacement and is provided With a compressi- 6. A mufiiing attachment comprising a ble facing adapted to bear on an end face tubular casing having a mouth iece at one of said telephone part. end, a socket at the opposite end adapted to In testimony whereof I have aiiixed my g detachably engage the body of a telephone signature,-in presence of two Witnesses. 30 transmitter, and intermediate means within LAWRENCE B GRAY the casing for detachably engaging the mouthpiece of the transmitter, said socket being composed of a cylindrical portion provided with an inner layer'of compressible Witnesses:

C. F. BROWN, J. MUnrnY.

It is hereby certified that in Letters Patent No. 1,177,61 7, granted April 4,1916 upon the application of Laivrence Bg G'ray, of Boston, Massachusetts, for an improvement in Sound- MufliingiAttachments for Telephonic Apparatus, an error appears the printed specification requiring correction as follows: Page claim 5, after line 25 insert the words and syllables tz'ally subdividing the outer air chamber.; and that the said Letters Patent should be read with this correction therein that the same may conformto the record of the case in the Patent Oflice.

Signed and sealed this 9th day of May, A. D., 1916.

[SEAL] a, F. WHITEHEAD,

A t. 0 I u I V 01. 179 188. amg ommtsstoner of Patents.

Correctionin Letters Patent No. 1.1 77,61 7. 

